The present invention relates to a hard surface cleaning composition containing a charged surfactant-polymer complex.
This invention relates to an improved all-purpose liquid cleaner designed in particular for cleaning hard surfaces including toilet bowls and which is effective in removing grease soil and/or bath soil and in leaving unrinsed surfaces with a shiny appearance.
In recent years all-purpose liquid detergents have become widely accepted for cleaning hard surfaces, e.g., painted woodwork and panels, tiled walls, wash bowls, bathtubs, linoleum or tile floors, washable wall paper, etc. Such all-purpose liquids comprise clear and opaque aqueous mixtures of water-soluble synthetic organic detergents and water-soluble detergent builder salts. In order to achieve comparable cleaning efficiency with granular or powdered all-purpose cleaning compositions, use of water-soluble inorganic phosphate builder salts was favored in the prior art all-purpose liquids. For example, such early phosphate-containing compositions are described in U.S. Pat. Nos. 2,560,839; 3,234,138; 3,350,319; and British Patent No. 1,223,739.
In view of the environmentalist""s efforts to reduce phosphate levels in ground water, improved all-purpose liquids containing reduced concentrations of inorganic phosphate builder salts or non-phosphate builder salts have appeared. A particularly useful self-opacified liquid of the latter type is described in U.S. Pat. No. 4,244,840.
However, these prior art all-purpose liquid detergents containing detergent builder salts or other equivalent tend to leave films, spots or streaks on cleaned unrinsed surfaces, particularly shiny surfaces. Thus, such liquids require thorough rinsing of the cleaned surfaces which is a time-consuming chore for the user.
In order to overcome the foregoing disadvantage of the prior art all-purpose liquid, U.S. Pat. No. 4,017,409 teaches that a mixture of paraffin sulfonate and a reduced concentration of inorganic phosphate builder salt should be employed. However, such compositions are not completely acceptable from an environmental point of view based upon the phosphate content. On the other hand, another alternative to achieving phosphate-free all-purpose liquids has been to use a major proportion of a mixture of anionic and nonionic detergents with minor amounts of glycol ether solvent and organic amine as shown in U.S. Pat. No. 3,935,130. Again, this approach has not been completely satisfactory and the high levels of organic detergents necessary to achieve cleaning cause foaming which, in turn, leads to the need for thorough rinsing which has been found to be undesirable to today""s consumers.
Another approach to formulating hard surfaced or all-purpose liquid detergent composition where product homogeneity and clarity are important considerations involves the formation of oil-in-water (o/w) microemulsions which contain one or more surface-active detergent compounds, a water-immiscible solvent (typically a hydrocarbon solvent), water and a xe2x80x9ccosurfactantxe2x80x9d compound which provides product stability. By definition, an o/w microemulsion is a spontaneously forming colloidal dispersion of xe2x80x9coilxe2x80x9d phase particles having a particle size in the range of 25 to 800 xc3x85 in a continuous aqueous phase.
In view of the extremely fine particle size of the dispersed oil phase particles, microemulsions are transparent to light and are clear and usually highly stable against phase separation.
Patent disclosures relating to use of grease-removal solvents in o/w microemulsions include, for example, European Patent Applications EP 0137615 and EP 0137616xe2x80x94Herbots et al; European Patent Application EP 0160762xe2x80x94Johnston et al; and U.S. Pat. No. 4,561,991xe2x80x94Herbots et al. Each of these patent disclosures also teaches using at least 5% by weight of grease-removal solvent.
It also is known from British Patent Application GB 2144763A to Herbots et al, published Mar. 13, 1985, that magnesium salts enhance grease-removal performance of organic grease-removal solvents, such as the terpenes, in o/w microemulsion liquid detergent compositions. The compositions of this invention described by Herbots et al. require at least 5% of the mixture of grease-removal solvent and magnesium salt and preferably at least 5% of solvent (which may be a mixture of water-immiscible non-polar solvent with a sparingly soluble slightly polar solvent) and at least 0.1% magnesium salt.
However, since the amount of water immiscible and sparingly soluble components which can be present in an o/w microemulsion, with low total active ingredients without impairing the stability of the microemulsion is rather limited (for example, up to 18% by weight of the aqueous phase), the presence of such high quantities of grease-removal solvent tend to reduce the total amount of greasy or oily soils which can be taken up by and into the microemulsion without causing phase separation.
The following representative prior art patents also relate to liquid detergent cleaning compositions in the form of o/w microemulsions: U.S. Pat. No. 4,472,291xe2x80x94Rosario; U.S. Pat. No. 4,540,448xe2x80x94Gauteer et al; U.S. Pat. No. 3,723,330xe2x80x94Sheflin; etc.
Liquid detergent compositions which include terpenes, such as d-limonene, or other grease-removal solvent, although not disclosed to be in the form of o/w microemulsions, are the subject matter of the following representative patent documents: European Patent Application 0080749; British Patent Specification 1,603,047; 4,414,128; and 4,540,505. For example, U.S. Pat. No. 4,414,128 broadly discloses an aqueous liquid detergent composition characterized by, by weight:
(a) from 1% to 20% of a synthetic anionic, nonionic, amphoteric or zwitterionic surfactant or mixture thereof;
(b) from 0.5% to 10% of a mono- or sesquiterpene or mixture thereof, at a weight ratio of (a):(b) being in the range of 5:1 to 1:3; and
(c) from 0.5% 10% of a polar solvent having a solubility in water at 15xc2x0 C. in the range of from 0.2% to 10%. Other ingredients present in the formulations disclosed in this patent include from 0.05% to 2% by weight of an alkali metal, ammonium or alkanolammonium soap of a C13-C24 fatty acid; a calcium sequestrant from 0.5% to 13% by weight; non-aqueous solvent, e.g., alcohols and glycol ethers, up to 10% by weight; and hydrotropes, e.g., urea, ethanolamines, salts of lower alkylaryl sulfonates, up to 10% by weight. All of the formulations shown in the Examples of this patent include relatively large amounts of detergent builder salts which are detrimental to surface shine.
A pH neutral microemulsion composition based on paraffin sulfonate and ethoxylated nonionic surfactant is able to deliver improved grease cleaning versus built, alkaline compositions. Besides the improved grease cleaning, this approach is much safer to surfaces as well as less aggressive on consumer""s hands (Loth et alxe2x80x94U.S. Pat. No. 5,075,026).
The microemulsion technology provides outstanding oil uptake capacity because of the adjustment of the curvature of the surfactant micelles by the molecules of the cosurfactant. Rod-like micelles are preferred as they can xe2x80x9cswallowxe2x80x9d oil to become globular without increasing the surface of contact between the hydrophobic core of the micelle and the hydrophilic continuous phase.
In diluted usage however, the microemulsion state is usually lost and the cleaning performance relies on the adsorption efficacy and leaving character of the surfactant system. Nonionic surfactants perform very well on grease, as they are excellent grease xe2x80x9csolubilizersxe2x80x9d. Actually, they spontaneously form swollen micelles. In moderate climate countries such as the northern states of the United States and the northern countries of Europe, the soil on the hard surfaces contains a major proportion of greasy materials. It is accordingly not surprising that the anionic-nonionic surfactant based microemulsion is very efficient in those countries. However, nonionic surfactants do not impart oil repelling properties and can not deliver soil antiattachment properties on treated hard surfaces so as to achieve next time easier cleaning of said treated surface.
The instant invention teaches hard surface cleaning containing a charged complex of an anionic surfactant which is an alkali metal salt such as sodium of a fluoroalkyl sulfonate, or an ammonium salt of a fluoroalkyl sulfonate, or a mixture thereof, which exhibits very low surface tensions, with either poly[4-vinyl pyridine N-oxide] or polyvinyl pyridine betaine which imparts oil repelling properties and delivers soil antiattachment properties on treated hard surfaces.
The present invention provides an improved, clear, liquid hard surface cleaning composition having improved interfacial tension which improves cleaning hard surfaces such as plastic, vitreous and metal surfaces having a shiny finish, oil stained floors, automative engines and other engines. More particularly, the improved cleaning compositions exhibit good grease soil removal properties and leave the cleaned surfaces shiny without the need of or requiring only minimal additional rinsing or wiping. The latter characteristic is evidenced by little or no visible residues on the unrinsed cleaned surfaces and, accordingly, overcomes one of the disadvantages of prior art products. The instant compositions exhibit a grease release effect in that the instant compositions impede or decrease the anchoring of greasy soil on surfaces that have been cleaned with the instant compositions as compared to surfaces cleaned with a microemulsion composition which means that the grease soiled surface is easier to clean upon subsequent cleanings.
Surprisingly, these desirable results are accomplished even in the absence of polyphosphate or other inorganic or organic detergent builder salts and also in the complete absence or substantially complete absence of grease-removal solvent.
In one aspect, the invention generally provides a stable, clear all-purpose, hard surface cleaning composition especially effective in the removal of oily and greasy oil. The cleaning composition includes, on a weight basis:
about 0.1% to about 20%, more preferably about 0.2% to about 15% of a charged complex comprising at least one alkali metal salt of a fluoroalkyl sulfonate surfactant, or at least one ammonium salt of a fluoroalkyl sulfonate surfactant, or mixtures thereof, and either poly[4-vinyl pyridine N-oxide] or polyvinylpyridine betaine;
about 0 to about 25%, more preferably 1% to 20%, of a water-mixable cosurfactant having either limited ability or substantially no ability to dissolve oily or greasy soil; and
the balance being water, said proportions being based upon the total weight of the composition.
The cleaning composition can be in the form of a microemulsion in which case the concentration of the water mixable cosurfactant is about 0 to about 25 wt. %, preferably about 1 wt. % to about 20 wt. % and the concentration of a perfume or water insoluble hydrocarbon is about 0.4 wt. % to about 5.0 wt. %. The dispersed oil phase of the o/w microemulsion is composed essentially of a water-immiscible or hardly water-soluble perfume.
The present invention relates to a stable all purpose hard surface cleaning or microemulsion composition containing a surfactant-polymer complex for delivering soil antiattachment properties. The invention also relates to a light duty liquid composition or light duty liquid microemulsion composition. This present inventeion is also useful in the formation of toilet bowl cleaners.
The present invention relates to a stable hard surface cleaning composition approximately by weight: 0.1% to 20% of a charged complex of an alkali metal salt of a fluoroalkyl sulfonate surfactant, or an ammonium salt of a fluoroalkyl sulfonate surfactant, or mixtures thereof, and a vinyl pyridine compound selected from the group consisting of poly[4-vinyl pyridine N-oxide] (PVNO) having an average molecular weight of 20,000 to 50,000 and polyvinyl pyridine betaine (PVB) having a molecular weight of 10,000 to 250,000 and mixtures thereof, 0 to 25% of a cosurfactant, and the balance being water, wherein the cleaning composition can be in the form of a microemulsion in which case the concentration of the water mixable cosurfactant is about 0 to about 25.0 wt. %, preferably about 0.1 wt. % to about 25.0 wt. % and the concentration of a perfume or water insoluble hydrocarbon is about 0.4 wt. % to about 5.0 wt. %.
When mixing an alkali metal salt such as the sodium salt of a fluorinated anionic surfactant, or an ammonium salt of a fluorinated anionic surfactant, or a mixture thereof, and a polymer bearing positively charged sites or highly dipolar groups along its backbone, attractive interactions are developed that are very strong and lead to the formation of anionic-cationic complexes in-situ. The complex interactions take place along the polymer backbone, so that surfactant-polymer complexes exist in solution. Attention must be paid not to complex all the positively charged sites or all the highly dipolar groups on the polycationic polymer so as to still have enough electric charges or highly dipolar groups on the whole structure so as to keep the complex water soluble (otherwise phase separation or precipitation might occur). The presence of positive charges on the surfactant-polymer system allows subsequent anchorage on substrate surface for modifying the surface energy.
One of the objects of the instant invention is to deliver higher proportions of a fluoroalkyl anionic surfactant in the adsorbed layer at the solid-water interface by means of surfactant-polymer mixtures. This is due to a boosted adsorption tendency, as compared to fluoroalkyl anionic individual surfactant, by means of neutralization between the negative charge of the anionic surfactant and the positive charge of the polymer, or by means of strongly attractive interactions between the negative charge of the anionic surfactant and the positive side of dipolar groups of the polymer that is used in admixture with the anionic surfactant in the instant compositions, and due to an increased hydrophobic character imparted to the polymer by the anionic surfactant linked to its backbone. Two anionic surfactants can be used in composition wherein one of the anionic surfactants will possibly preferentially associate with the polymer through electrostatic interactions.
According to the present invention, the role of the hydrocarbon is provided by a non-water-soluble perfume. Typically, in aqueous based compositions the presence of a solubilizers, such as alkali metal lower alkyl aryl sulfonate hydrotrope, triethanolamine, urea, etc., is required for perfume dissolution, especially at perfume levels of 1% and higher, since perfumes are generally a mixture of fragrant essential oils and aromatic compounds which are generally not water-soluble. Therefore, by incorporating the perfume into the aqueous cleaning composition as the oil (hydrocarbon) phase of the ultimate o/w microemulsion composition, several different important advantages are achieved.
First, the cosmetic properties of the ultimate cleaning composition are improved: the compositions are both clear (as a consequence of the formation of a microemulsion) and highly fragranced (as a consequence of the perfume level).
Second, the need for use of solubilizers, which do not contribute to cleaning performance, is eliminated.
Third, an improved grease release effect and an improved grease removal capacity in neat (undiluted) usage of the composition or after dilution of the composition can be obtained without detergent builders or buffers or conventional grease removal solvents at neutral or acidic pH and at low levels of active ingredients while improved cleaning performance can also be achieved in diluted usage.
As used herein and in the appended claims the term xe2x80x9cperfumexe2x80x9d is used in its ordinary sense to refer to and include any non-water soluble fragrant substance or mixture of substances including natural (i.e., obtained by extraction of flower, herb, blossom or plant), artificial (i.e., mixture of natural oils or oil constituents) and synthetically produced substance) odoriferous substances. Typically, perfumes are complex mixtures of blends of various organic compounds such as alcohols, aldehydes, ethers, aromatic compounds and varying amounts of essential oils (e.g., terpenes) such as from 0% to 80%, usually from 10% to 70% by weight. The essential oils themselves are volatile odoriferous compounds and also serve to dissolve the other components of the perfume.
In the present invention the precise composition of the perfume is of no particular consequence to cleaning performance so long as it meets the criteria of water immiscibility and having a pleasing odor. Naturally, of course, especially for cleaning compositions intended for use in the home, the perfume, as well as all other ingredients, should be cosmetically acceptable, i.e., non-toxic, hypoallergenic, etc.
The hydrocarbon such as a perfume is present in the hard surface cleaning composition in an amount of from 0 to 5% by weight, preferably 0.4% to 5% by weight, more preferably from 0.4% to 3.0% by weight, especially preferably from 0.5% to 2.0% by weight. If the hydrocarbon (perfume) is added in amounts more than 5% by weight, the cost is increased without any additional cleaning benefit and, in fact, with some diminishing of cleaning performance insofar as the total amount of greasy or oily soil which can be taken up in the oil phase of the microemulsion will decrease proportionately.
Furthermore, although superior grease removal performance will be achieved for perfume compositions not containing any terpene solvents, it is apparently difficult for perfumers to formulate sufficiently inexpensive perfume compositions for products of this type (i.e., very cost sensitive consumer-type products) which includes less than 20%, usually less than 30%, of such terpene solvents.
Thus, merely as a practical matter, based on economic consideration, the microemulsion compositions of the present invention may often include as much as 0.2% to 7% by weight, based on the total composition, of terpene solvents introduced thereunto via the perfume component. However, even when the amount of terpene solvent in the cleaning formulation is less than 1.5% by weight, such as up to 0.6% by weight or 0.4% by weight or less, satisfactory grease removal and oil removal capacity is provided by the inventive diluted microemulsions.
In place of the perfume one can employ a water insoluble paraffin or isoparaffin having 6 to 18 carbon at a concentration of 0 to 5 wt. percent, preferably 0.4 to 5.0 wt. percent, more preferably 0.4 to 3.0 wt. %.
The charged complex contained in the instant compositions comprises a complex of:
(a) an alkali metal salt such as sodium of a fluoroalkyl sulfonate anionic surfactant, or an ammonium salt of a fluoroalkyl sulfonate anionic surfactant, or mixtures thereof; and
(b) a polymer which is selected from the group consisting of poly[4-vinyl pyridine N-oxide] (PVNO) and polyvinyl pyridine betaine (PVB) and mixtures thereof, wherein the molar ratio of the anionic surfactant to the highly dipolar or positively charged binding sites available on the polymer backbone is 0.95:1 to 0.05:1, more preferably 0.9:1 to 0.1:1. The instant composition contains about 0.1 to about 20 wt. %, more preferably about 0.2 to about 15 wt. % of the charged complex.
The fluoroalkyl sulfonate anionic surfactant which has a RF fluoroalkyl group which is a C16F33 to C5F11, preferably a C6F13 to C10F21 fluoroalkyl group and can be selected among the different compounds being depicted by the following structures of, perfluoroalkane sulfonate salt:
RFxe2x80x94SO3xe2x88x92X+
perfluoroalkylethane sulfonate salt: 
perfluoroalkyl group containing sulfonate with sulfide and carbonamide linkages: 
wherein, X can be an alkali metal counterion such as sodium, or an ammonium counterion such as NH4+, and R1 and R2 are H or methyl groups.
A cosurfactant can be optionally used in forming the microemulsion composition. A major class of compounds have been found to provide highly suitable cosurfactants over temperature ranges extending from 5xc2x0 C. to 43xc2x0 C., for instance, water-soluble C3-C4 alkanols, polyethylene glycols of the formula HO(CH2CH2O)nH wherein n is about 8 to about 14, polypropylene glycol of the formula HO(CH3CHCH2O)nH wherein n is a number from 2 to 18 and copolymers of ethylene oxide and propylene oxide and mono C1-C6 alkyl ethers and esters of ethylene glycol and propylene glycol having the structural formulas R(X)nOH and R1(X)nOH wherein R is C1-C6 alkyl, R1 is C2-C4 acyl group, X is (OCH2CH2) or (OCH2(CH3)CH) and n is a number from 1 to 4.
Representative members of the polypropylene glycol include dipropylene glycol and polypropylene glycol having a molecular weight of 200 to 1000, e.g., polypropylene glycol 400. Other satisfactory glycol ethers are ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol monobutyl ether (butyl carbitol), propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, triethylene glycol monobutyl ether, mono, di, tri propylene glycol monobutyl ether, tetraethylene glycol monobutyl ether, triethylene glycol monohexyl ether, tetraethylene glycol monohexyl ether, pentaethylene glycol monohexyl ether, propylene glycol tertiary butyl ether, ethylene glycol monoacetate and dipropylene glycol propionate.
The amount of cosurfactant which might be required to stabilize the microemulsion compositions will, of course, depend on such factors as the surface tension characteristics of the cosurfactant, the type and amounts of the complex and perfumes, and the type and amounts of any other additional ingredients which may be present in the composition and which have an influence on the thermodynamic factors enumerated above. Generally, amounts of cosurfactant in the range of from 0 to 25 wt. %, preferably from 0.5 wt. % to 15 wt. %, especially preferably from 1 wt. % to 7 wt. %, provide stable microemulsions for the above-described levels of primary surfactants and perfume and any other additional ingredients as described below.
An optional ingredient for use herein is an inorganic or organic salt of oxide of a multivalent metal cation, particularly Mg++. The metal salt or oxide provides several benefits including improved cleaning performance in dilute usage, particularly in soft water areas, and minimized amounts of perfume required to obtain the microemulsion state. Magnesium sulfate, either anhydrous or hydrated (e.g., heptahydrate), is especially preferred as the magnesium salt. Good results also have been obtained with magnesium oxide, magnesium chloride and magnesium hydroxide. These magnesium salts can be used with formulations at neutral or acidic pH since magnesium hydroxide will not precipitate at these pH levels.
Although magnesium is the preferred multivalent metal from which the salts (inclusive of the oxide and hydroxide) are formed, other polyvalent metal ions also can be used provided that their salts are nontoxic and are soluble in the aqueous phase of the system at the desired pH level.
Thus, depending on such factors as the pH of the system, the nature of the surfactant-polymer complex and cosurfactant, as well as the availability and cost factors, other suitable polyvalent metal ions include aluminum, copper, nickel, iron, calcium, etc. It should be noted, for example, that with the preferred fluoroalkyl sulfonate anionic detergent calcium salts will precipitate and should not be used. It has also been found that the aluminum salts work best at pH below 5. As the salt, the same general classes of anions as mentioned for the magnesium salts can be used, such as halide (e.g., bromide, chloride), sulfate, nitrate, hydroxide, oxide, etc.
The proportion of the multivalent salt generally will be selected so that at the appropriate weight ratio between the anionic surfactant and the polymer to deliver desired performance from the surfactant-polymer mixture in terms of adsorption properties on hard surfaces and soil antiattachment on treated hard surfaces, the physical stability of the total composition is kept, that can be impaired due to an increased hydrophobicity of the anionic surfactant in the presence of multivalent salt instead of alkali metal cation such as the sodium salt thereof. As a consequence, the proportion of the multivalent salt will be selected so that the added quantity will neutralize from 0.1 to 1.5 equivalents of the anionic surfactant, preferably 0.9 to 1.4 equivalents of the acid form of the anionic surfactant. At higher concentrations of anionic surfactant, the amount of multivalent salt will be in range of 0.5 to 1 equivalents per equivalent of anionic surfactant.
The all-purpose liquid cleaning or microemulsion composition of this invention may, if desired, also contain other components either to provide additional effect or to make the product more attractive to the consumer. The following are mentioned by way of example: Colors or dyes in amounts up to 0.5% by weight; bactericides in amounts up to 1% by weight; preservatives or antioxidizing agents, such as formalin, 5-chloro-2-methyl-4-isothaliazolin-3-one, 2,6-di-tert.butyl-p-cresol, etc., in amounts up to 2% by weight; and pH adjusting agents, such as sulfuric acid or sodium hydroxide, as needed. Furthermore, if opaque compositions are desired, up to 4% by weight of an opacifier may be added.
The instant compositions can contain 0 to 4 wt. %, more preferably 0.05 to 3.0 wt. % of a proton donating agent selected consisting of inorganic acids such as sulfuric, hydrochloric or phosphoric acid and organic acids such as alpha hydroxy aliphatic acids, mono or dicarboxylic acids having 4 to 10 carbon atoms and mixtures thereof.
In final form, the all-purpose cleaning or clear microemulsions exhibit stability at reduced and increased temperatures. More specifically, such compositions remain clear and stable in the range of 40xc2x0 C. to 50xc2x0 C., especially 10xc2x0 C. to 43xc2x0 C. Such compositions exhibit a pH in the acidic to neutral range depending on intended end use. The liquids are readily pourable and exhibit a viscosity in the range of 6 to 60 milliPascal.Second (mPas.) as measured at 25xc2x0 C. with a Brookfield RVT Viscometer using a #1 spindle rotating at 20 RPM. Preferably, the viscosity is maintained in the range of 10 to 40 mPas.
The compositions are directly ready for use or can be diluted as desired and in either case no or only minimal rinsing is required and substantially no residue or streaks are left behind. Furthermore, because the compositions are free of detergent builders such as alkali metal polyphosphates they are environmentally acceptable and provide a better xe2x80x9cshinexe2x80x9d on cleaned hard surfaces.
When intended for use in the neat form, the liquid compositions can be packaged under pressure in an aerosol container or in a pump-type sprayer for the so-called spray-and-wipe type of application.
Because the compositions as prepared are aqueous liquid formulations and since no particular mixing is required to form the all purpose cleaning or microemulsion compositions, the compositions are easily prepared simply by combining all the ingredients in a suitable vessel or container. The order of mixing the ingredients is not particularly important and generally the various ingredients can be added sequentially or all at once or in the form of aqueous solutions of each or all of the primary detergents and cosurfactants can be separately prepared and combined with each other and with the perfume. The magnesium salt, or other multivalent metal compound, when present, can be added as an aqueous solution thereof or can be added directly. It is not necessary to use elevated temperatures in the formation step and room temperature is sufficient.
The instant all purpose cleaning or microemulsion composition explicitly exclude alkali metal silicates and alkali metal builders such as alkali metal polyphosphates, alkali metal carbonates, alkali metal phosphonates and alkali metal citrates because these materials, if used in the instant composition, would cause the composition to have a high pH as well as leaving residue on the surface being cleaned.
It is contemplated within the scope of the instant invention that the instant charged surfactant-polymer complex can be employed in hard surface cleaning compositions such as wood cleaners, window cleaners and light duty liquid cleaners.